Influence of costimulating factors FLT3 ligand (FL) and SCF and negative regulators on colony formation by CFU-GM from BM of WT control (CD1d+/+) and CD1d−/− mice on a C57Bl/6 background. (A) Co-stimulating factors, and (B) negative regulators. The average results ± SEM from 3 separate experiments each for CD1d+/+ and CD1d−/− mice are shown. In panel A, asterisk designates significant differences of GM-CSF or IL-3 in combination with SCF and/or FL compared with either GM-CSF– or IL-3 alone–stimulated culture, P < .003. Colony formation for panel B was stimulated by erythropoietin (Epo), PWMSCM, SCF, and hemin, and cells plated in the absence and presence of 10 ng/mL of TNF-α, 10 ng/mL of IFN-γ, or 10 ng/mL of the chemokines MIP-1α/CCL3, ENA-78/CXCL5, or IL-8/CXCL8. NS indicates not significant (P > .05).